I would like to build a custom form, so when a user signs up through active campaign they are then presented with a second form. With the second form they can choose which categories they want to recieve emails for.
I have done some research and think I have to use the API provided by active campaign, but I have no idea how to go about it.
This is their API http://www.activecampaign.com/api/overview.php
Anyone got any pointers for me to get me started.
Read more here: Working with active campaign api